Gas operated dispensing devices for viscous products such as adhesives or caulks are known. The gas for driving such viscous product dispensing devices has been supplied by a pressurized gas cartridge. Typically, however, such a pressurized gas cartridge has a fairly limited supply of pressurized gas. For example, commercially available pressurized CO2 cartridges typically come in 12, 16 and 25 gram sizes. Thus, it is necessary to frequently replace such pressurized gas cartridges. Of course, such frequent replacement operations can significantly disrupt product dispensing. The disruption can be magnified, for example, when it is necessary to locate and retrieve a replacement pressurized CO2 cartridge from a storage location that is separate from the dispensing device. Such frequent disruption of the dispensing operation can meaningfully increase the time required to complete a caulk or adhesive product application.